Hierarchical representation of hypotheses of homology

Tables (usually called data matrices) are currently used to represent hypotheses of homology in cladistic analysis because they are easily readable and concise. Williams & Ebach (2006) have recently criticized their use. They argue that tables are unable to represent nested relationships and the underlying homologies. We agree with their point of view and we supplement their argumentation. We identify the formal reasons of the inadequacy of this kind of representation in systematics and cladistic biogeography. We propose a solution that has the advantage of being easily understandable and concise as well. In order to guarantee consistency in the representation proposed herein, we provide precise definitions of the concepts of “component”, “character”, “character-state”, and “homologue”.